Why the war with Iran?

The maddeningly loud war chants against Iran--from the US and Israel--worry me a lot. Israel couldn't even win its battle with Hezbollah in Lebanon, and wants to go after a way larger target? And we are stuck in Iraq and Afghanistan, and with a rapidly weakening economy ....
A single bomb dropped over Iran will push the world over the ultimate tipping point towards a chaos that can be beyond the wildest imagination.

Here is an excerpt from the NY Review of Books:
At a moment of serious challenge, battered by two wars, ballooning debt, and a faltering economy, the United States appears to have lost its capacity to think clearly. Consider what passes for national discussion on the matter of Iran. The open question is whether the United States should or will attack Iran if it continues to reject American demands to give up uranium enrichment. Ignore for the moment whether the United States has any legal or moral justification for attacking Iran. Set aside the question whether Iran, as Secretary of Defense Robert Gates recently claimed in a speech at West Point, "is hellbent on acquiring nuclear weapons." Focus instead on purely practical questions. By any standards Iran is a tough nut to crack: it is nearly three times the size of Texas, with a population of 70 million and a big income from oil which the world cannot afford to lose. Iran is believed to have the ability to block the Straits of Hormuz in the Persian Gulf through which much of the world's oil must pass on its way to market.

Keep in mind that the rising price of oil already threatens the world's economy. Iran also has a large army and deep ties to the population of Shiite coreligionists next door in Iraq. The American military already has its hands full with a hard-to-manage war in Iraq, and is proposing to send additional combat brigades to deal with a growing insurgency in Afghanistan. And yet with all these sound reasons for avoiding war with Iran, the United States for five years has repeatedly threatened it with military attack. These threats have lately acquired a new edge.